Today, usage of high speed point-to-point data links, such as serial and parallel data links, between electronic devices are very common. Exemplary high speed serial data links in storage applications include, peripheral component interconnect express (PCIe), serial attached small computer system interface (SAS), serial advanced technology attachment (SATA), fiber channel (FC) and the like.
Due to the rising data transmission rates, these data links are currently driven at data rates of several gigabits per second. As a result of such high data transmission and receive rates, any type of probing of the data links may lead to adverse effects on signal integrity and may result in problems in reception and transmission of data between the electronic devices.
Typically, an analyzer may be used to test, debug and diagnose any data or protocol sent using such data links. Generally, testing is done by inserting an analyzer between two or more electronic devices by breaking the data links so that the data exchanged between the electronic devices flows in and out of the analyzer. This type of testing, typically, addresses the signal integrity issues, however, this technique is limited by the fact that it requires breaking the data links, which implies that only the physically accessible data links (such as a cable connecting two or more electronic devices) can be broken for analyzing the data exchanged between the electronic devices. Further, the above approach may not be feasible for use in embedded data links, such as data links embedded in inner layers of a printed circuit board (PCB) as there are no cables used in connecting the electronic devices.
Furthermore, the above approach may not be feasible for electronic devices that have physically inaccessible data links. Exemplary inaccessible data links include motherboards having embedded storage processors wherein the PCIe data link directly connects between the northbridge and a controller on the PCB. Another exemplary inaccessible data links is a storage enclosure backplane where connecting a SAS analyzer between a backplane and a drive is nearly inaccessible due to the tight space. Yet another exemplary inaccessible data links is a server backplane where the SAS analyzer is connected between backplane and the drive. Moreover, in the above testing approach, the analyzer needs to have the capability to transmit back the received data and this can be cumbersome and expensive.